This report from Rasmussen.
The germane excerpt is this one:
Thirty-nine percent (39%) of voters in the South Carolina Republican Primary say they're affiliated with the Tea Party movement.
A significant majority of those who support the Tea Party say they voted for Nikki Haley, who won a plurality of votes in the state's GOP gubernatorial primary. You'll recall that Ms. Haley's campaign received a significant boost when she was endorsed by Sarah Palin, a favorite of the Tea Party movement.
Snicker at the Tea Party movement all you like. Call these people mad for no good reason. Call these people out of touch. But don't be surprised if they vote in strong enough blocks to knock out one of your favorite politicians.